Factor Completely $3 a ^ { 2 } + 4 a - 15$

Multiple Choice

Factor completely. $3 a ^ { 2 } + 4 a - 15$

A) $( 3 a - 1 ) ( a + 15 )$
B) $( 3 a + 5 ) ( a - 3 )$
C) $( 3 a - 15 ) ( a + 1 )$
D) $( 3 a - 5 ) ( a + 3 )$
E) Not factorable